Messages in this thread | | | Date | Fri, 18 May 2018 12:05:28 -0700 | Subject | Re: [PATCH 2/6] x86: bug: prevent gcc distortions | From | hpa@zytor ... |
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On May 18, 2018 12:02:50 PM PDT, Nadav Amit <namit@vmware.com> wrote: >hpa@zytor.com wrote: > >> On May 18, 2018 11:50:12 AM PDT, Linus Torvalds ><torvalds@linux-foundation.org> wrote: >>> On Fri, May 18, 2018 at 11:34 AM <hpa@zytor.com> wrote: >>> >>>> On May 18, 2018 11:25:32 AM PDT, Linus Torvalds < >>> torvalds@linux-foundation.org> wrote: >>> >>>> Unfortunately gcc doesn't guarantee that global assembly inlines >will >>> appear at the top of the file. >>> >>> Yeah. It really would be better to do the "asm version of -inline". >>> >>> We already do something like that for real *.S files on some >>> architectures >>> (because their assembly really wants it, eg >>> >>> arch/arm/Makefile: >>> KBUILD_AFLAGS +=$(CFLAGS_ABI) $(AFLAGS_ISA) $(arch-y) $(tune-y) >>> -include >>> asm/unified.h -msoft-float >>> >>> but I do want to point out that KBUILD_AFLAGS is *not* used for >>> compiler-generated assembly, only for actual *.S files. >>> >>> Sadly, I don't actually know any way to make gcc call the 'as' phase >>> with >>> particular options. We can use "-Wa,xyzzy" to pass in xyzzy to the >>> assembler, but there is no "-include" option for GNU as afaik. >>> >>> Can you perhaps define a macro symbol for "--defsym"? Probably not. >>> >>> Linus >> >> I looked at this thing a long time ago; it's not there, and the best >would probably be to get global asm() working properly in gcc. > >I can add a -Wa,[filename.s] switch. It works, but sort of >undocumented.
Ah, I thought that would have assembled each file separately. We can request it be documented, that's usually much easier than getting a new feature implemented. -- Sent from my Android device with K-9 Mail. Please excuse my brevity.
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